101 votes
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Can HIV be transmitted via mosquitos?

No, this is not possible. There are a few reasons for that, but most important are that the only thing a mosquito injects is its own saliva, while the blood is sucked into the stomach where it is ...
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56 votes

What is the benefit of fever during infections?

Fever is a trait observed in warm and cold-blooded vertebrates that has been conserved for hundreds of millions of years (Evans, 2015). Elevated body temperature stimulates the body's immune ...
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  • 51k
42 votes
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Why do diseases in the tap water of developing countries affect people from developed countries more?

You can expect that someone drinking from a water source regularly will develop immunity to the pathogens in that water source by being repeatedly exposed to them. However, it's not quite right to say ...
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  • 35k
36 votes
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Specific mechanism behind lethality of yellow coat color in mice

Really interesting question: The lethal yellow mutation (also abbreviated Ay) affects the agouti signalling protein which plays a major role in pigmentation. Heterozygous expression of it leads to the ...
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19 votes
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What kind of fly is this?

This is probably a fly killed by the fungi Entomophthora muscae (or closely related) or maybe a Cordyceps fungus. These kinds of fungi mainly attacks insects, and you sometimes see attacks as white, ...
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18 votes
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Why is an HIV infection considered "incurable"?

The reasons why HIV is "incurable" (a misnomer) are legion: HIV is a retrovirus, which means it inserts its own genome into the host cell's genome. You must therefore kill each and every infected ...
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  • 9,702
17 votes

Why doesn't blood remain on a mosquito's proboscis in quantities that could spread blood-borne diseases?

A mosquito's proboscis isn't like that of a butterfly, which could easily have nectar clinging to it when it is coiled up; instead, consider that the part of the mosquito's proboscis that enters a ...
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17 votes
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Is COVID-19 claimed to get less deadly over time? If so, why?

While the data are much too sparse and noisy to give an answer about what is happening to COVID-19's virulence (the technical term for the "deadliness" of an infectious disease), or to forecast what ...
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  • 4,553
15 votes
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Can cancers caused due to viruses be contagious?

The question title and the question itself ask two slightly (but critically) different questions. Can cancers caused due to viruses be contagious? NO Are these oncoviruses infectious in nature? YES ...
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14 votes
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Why doesn't HDL cause diseases like LDL?

Thank you for the fascinating question! It was tough to research but very worthwhile. LDL is actually not such a bad molecule. It is formed from VLDL/IDL after VLDL/IDL distribute triglycerides, ...
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  • 1,634
12 votes

Why is the current Ebola outbreak different from previous outbreaks?

This is too long for a comment, so I put this in here: The main reasons are sociological. From the data I have read so far, this outbreak (actually these are two independent outbreaks, one in West-...
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12 votes

Why is cancer not a communicable disease?

A cancer is not a pathogen Cancer is a group of cells that (because of several specific mutations) start to duplicate abnormally. This group of cancerous cells are the own cells of the sick patient. ...
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12 votes
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Why do people with Down syndrome get fewer cancers?

This is a great question. Just to make it clear people with DS do have a reduced risk of solid cancers and an increased risk of blood cancers, (B-ALL and AML). You are correct in picking out DSRC1 ...
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12 votes
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Can androgen-insensitive genetic-males get pregnant?

Short answer People with androgen insensitivity syndrome do not have a functional uterus and cannot bear a child. Background Androgen-insensitive genetic males may develop female genitalia and ...
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12 votes

Can HIV be transmitted via mosquitos?

I am not a medical doctor but in my view this is within the realms of possibility. The probability has been estimated by Princeton at 1 in 10 million. This is per bite, assuming - I presume - that the ...
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12 votes
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Do colour blind people see white?

No not white or grey generally, it's a mix of other colors, they often have low resolution of a particular color. Here's a page where you can mouse over a color wheel and see a version in color ...
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12 votes

Can cancers caused due to viruses be contagious?

Yes, Oncoviruses are infectious in nature. A good example is the Human Papilloma Virus, which does not immediately cause cancer, but can cause precancerous lesions in infected regions including cervix,...
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11 votes

Can a bacteriophage be used to treat bacterial diseases?

Yes, this is possible and is researched as an alternative to antibiotics. It has been used experimentally before antibiotics became widely available. Research was abandoned when antibiotics became ...
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  • 49.1k
11 votes

Why is the current Ebola outbreak different from previous outbreaks?

For some background, it is essential to know that Ebola is actually a group (genus) of ebolaviruses, each with different fatality rates. There are five known species of Ebola, and four are known to ...
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11 votes
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Why does a Urinary Tract Infection cause a strong, persistent urge to urinate?

Nerve endings exist in a more or less homeostatic interstitial fluid medium which when disturbed in certain ways result in depolarization. This is a very simple explanation, but basically correct. ...
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11 votes

Why are men more susceptible to severe COVID-19?

Update -- In the time since this question was asked, two relevant articles have been published, one in Nature Reviews Immunology and one in medRxiv (note: medRxiv is a preprint server and is therefore ...
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  • 7,214
9 votes
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Why is the species-diversity of deadly parasites greatest in the tropics?

The diversity of parasites shows a gradient with increasing diversity from the poles to the equator. Several reasons have been brought forth to explain the latitude-dependency of parasite diversity: ...
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8 votes

Can people with paralyzed eye muscles see?

Short answer Visual perception persists in the absence of functional eye movement. Background An example case would be retinal implants wearers. Retinal implants like the Argus II consist of a set of ...
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8 votes

Can people with AIDS get tattoos?

Posted due to certain inaccuracies in comments and answers provided to this question regarding the Human Immunodeficiency Virus. It should be noted that while it may not affect the ability for ...
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8 votes
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how the coronavirus was distinguished?

This is basic epidemiology. When medical professionals notice that a group of people with some characteristic in common, are being seen for a similar disease, they ask if there's a connection. In this ...
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  • 14.1k
7 votes
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What is overdiagnosis?

Overdiagnosis and overtreatment are intertwined. There is debate about how to best describe the problem, but narrowly defined, overdiagnosis occurs when increasingly sensitive tests - or changing ...
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7 votes
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How "exactly" is Rabies transmitted?

This is actually far more complex a question than you probably know. The country you are writing from matters. There are some rabies virus variants that have a relatively low pathogenicity for humans (...
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7 votes
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What causes the range of severity of neurological deficits in Down's syndrome?

The symptoms of Down syndrome occur due to overexpression of genes present on the duplicated chromosome. If possessing an extra chromosome meant an equivalent change in gene expression, one would ...
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  • 35k
7 votes
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Why don't we build up an immunity to sore throat?

Short Answer It should be noted that there are many non-pathogenic causes of sore throat, and I would suspect that you are not always distinguishing these causes from actual illness. In most cases, ...
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7 votes

What is the benefit of fever during infections?

Fever normally under hypothalamic heat center's control which stays at limbic system of brain . Hypothalamus sets its own set point 36.4-37.2 in healthy peoples by some molecules named exogenous and ...
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